Living in Germany, we have here a German Ju-Jutsu.
It was developed from masters of karate, judo etc. for police, justice staff etc. as a new martial art. Since then several new material had been added.
It is organised in regional and national associations with a unified curriculum and belt-tests.
So it is nothing a single person invented, just to be a grand master.
Are there in other countries similar martial art styles?
The search engines always give me hits to bjj or offshoots from bjj.